1. Field of the Invention
The present invention relates to an electronic circuit device comprising a connector, a circuit board on which the connector is mounted, and a case for containing the above.
2. Description of the Related Art
The electronic circuit device of this type is disclosed, for example, in Japanese Patent Laid Open Publication No. 9-321462 of Japanese Patent Application No. 8-139186 filed on May 31, 1996 by KANSEI CORP.
In FIG. 10, the above described electronic circuit device has an upper case 1. There are formed continuous openings 2 and 3 in the upper case 1. The upper case 1 has a fitting flange 4 at a circumferential edge of the opening 2 so as to project outwardly. Boss portions 6 having a same height are integrally formed at inner four corners of an upper wall face 5 of the upper case 1. An electronic circuit board 8 equipped with an electronic component 7 is fitted to the boss portion 6 from a lower side by means of screws 9. A connector 10 adapted to be engaged with an exterior circuit (a mating connector) is fitted to the electronic circuit board 8 through the opening 3.
A plurality of lead terminals 12 of the connector 10 are soldered to the electronic circuit board 8. A projecting rib 14 is formed on an upper wall of a housing 13 of the connector 10 so as to project upward as seen in FIG. 11. When the connector 10 is received in the case, the projecting rib 14 is adapted to be engaged in a pair of projections 15, 15 which are formed on the upper wall face 5 of the upper case 1. Reference numeral 16 represents a lower case which is fixed to an edge portion of the opening 2 of the upper case 1 by means of screws.
In the above described prior art, when the connectors are mated, the projecting rib 14 of the connector 10 is abutted against the projections 15 of the upper case 1 to restrict movement of the connector. This eliminates a fear of breakdown of the electronic circuit board 8 and can enhance reliability.
However, in the conventional device, because a distance between the projections 15, 15 is narrow, careful attention must be paid to positional alignment when the connector 10 is placed in the upper case 1 for assembling. Therefore, not to speak of bad workability, the projecting rib 14 may not be engaged between the projections 15, 15 in some cases, and there has been a fear that the electronic circuit device may be assembled even though the connector 10 is contained in an unstable state.
Moreover, the fixing work of the connector 10 to the electronic circuit board 8 by means of the screws is annoying and adversely affects workability and cost.
The present invention has been made in view of the above circumstances, and it is an object of the invention to provide an electronic circuit device which can be reliably assembled with the improved workability.
In order to solve the above described problems, there is provided, according to a first aspect of the present invention, an electronic circuit device comprising a connector to be connected with an exterior circuit, a circuit board on which the connector and electronic components are mounted, and a case having an opening which is defined by end portions of its side walls, the connector and the circuit board being adapted to be received in the case through the opening, wherein the case includes guide recesses in a concave shape whose width becomes gradually narrower from the end portions of the side walls toward base end portions of the side walls, and the connector includes guide projections which are adapted to be guided along the guide recesses and are in a convex shape whose width becomes gradually broader from a side which is first inserted into the case toward the opposite side.
According to a second aspect of the present invention, both the guide recesses and the guide projections include inclined faces to form a V-shape.
According to a third aspect of the present invention, respective ones of the inclined faces of the guide recesses and the guide projections serve also as sealing faces.
According to a fourth aspect of the present invention, the connector is provided with positioning and supporting projections which are passed through the circuit board.
According to the first aspect of the present invention, the electronic circuit device consists of the connector provided with the guide projections, the circuit board on which the connector is mounted, and the case provided with the guide recesses. Since the guide recesses are broader in width at the end portions of the side walls of the case, and the guide projections are narrower in width at the side where the connector is first inserted, no high positional accuracy is required when the connector is received in the case. Because the guide projections are guided into the guide recesses, the connector will be never received in the case in an unstable state. Thus, the connector can be reliably contained in the case.
According to the second aspect of the present invention, the connector is contained in the case in such a manner that the guide projections are fitted in the guide recesses. Since an action received from the exterior circuit on occasion of engaging the connectors will be exerted on the guide recesses by way of the guide projections, concentration of a stress on the circuit board will be dispersed.
According to the third aspect of the present invention, when the connector has been contained in the case, the shielding performance between the case and the connector can be assured by the respective ones of the inclined faces of the guide recesses and the guide projections.
According to the fourth aspect of the present invention, by inserting the projections on the connectors into the circuit board, the connector can be positioned and supported. Therefore, work for fitting the connector to the circuit board by means of the screws as in the prior art can be eliminated.